The cockroach

I don't know if you guys have heard this one or not, but here goes anyway...

So this guy walks into a bar and sits down at a table, just looking for a place to relax. After a couple of minutes, the double doors to the bar SLAM open, and a HUGE man sized cockroach runs in and looks around, sees the man, and runs to him. He grabs the man by the collar and starts to punch him in the face and takes one of the chairs to his head. After proceeding to throw the man across the room, the roach runs back out the door, gone in an instant. The man crawls over to the counter, drags himself up, and says, "Oh... oh man, what just... what just happened!?"
Then the bartender replies, "Well, there's this really nasty bug goin around."